1. Field of the Invention
The present invention relates to a pressure-sensitive adhesive sheet with a release liner. More specifically, it relates to a pressure-sensitive adhesive sheet with a release liner which excels in die-cutting workability and releasability. In addition, it relates to a release liner for use with the pressure-sensitive adhesive sheet.
2. Description of the Related Art
Pressure-sensitive adhesive sheets (tacky adhesive sheets) generally include a pressure-sensitive adhesive layer (tacky adhesive layer) and a sheet material in contact with the pressure-sensitive adhesive layer and having releasability (hereinafter referred to as “release liner”), so that the release liner can be peeled off from the pressure-sensitive adhesive layer.
Such pressure-sensitive adhesive sheets with a release liner are used typically for the affixation of automotive emblems. In this use, a pressure-sensitive adhesive sheet (pressure-sensitive adhesive double-sided sheet) is die-cut into a shape corresponding to an emblem, one of two adhesive surfaces is affixed to the back surface of the emblem. The resulting emblem is generally stored while bearing a release liner on the other adhesive surface of the sheet, and the release liner is removed before use. Pressure-sensitive adhesive sheets with release liners for use in this use should have storage stability to avoid “lifting and unintended separation” of the release liner during storage, should satisfactorily undergo die-cutting, and should be sufficiently releasable upon use.
As release liners for use with pressure-sensitive adhesive sheets, there have been used release liners formed by applying a film of silicone release agent or the like through coating and curing the coated film. To save such coating process, release liners composed of polyethylene or polypropylene have been recently employed. Examples of these release liners can be found in Japanese Unexamined Patent Application Publication (JP-A) No. 2000-239624 corresponding to U.S. Pat. No. 6,395,360B; JP-A No. 2003-127299 corresponding to US20030077442A; and JP-A No. 2005-350650 corresponding to US20050266195A.
However, with increasing design features, automotive emblems have more and more complicated shapes, and pressure-sensitive adhesive sheets using these known release liners suffer from disadvantages in workability, such as poor die-cutting workability. Additionally, they also suffer from problems in handleability. For example, when the release liner is removed, insufficient peel may occur at the edge of the emblem, or deformation of a part of the emblem may occur under a high peel stress.
Not only in the above-mentioned use but also in other uses, there is a need of providing release liners and pressure-sensitive adhesive sheets that are satisfactorily worked through die-cutting and excel in releasability.